Please Help me identify this sci-fi book

I am failing at finding a book I read in the mid to late 70s or early 80s. It was a science fiction book set in the long-away future. I will post here the bits I remember. The protaganist of this book was a young boy who lived in a vast, enclosed city. He was the only child there as human lifetimes had be extended greatly, and childbirth was carefully controlled. He discovered deep beneath the city a transportation hub that connected with many other cities on Earth. This hub had gone unused for millions? of years. He also discovered a robot, and duplicated it with a replicating machine that hadn’t been used in the past 250,000 years. Did I mention humans had no teeth? This city has a “Master Assimilator” computer that kept track of everything. Ok, in his travels he met up with other humans who had briefer life spans, but possessed the ability to erase memories. His memories of the visit with them was to be erase. He carefully instructed his robot to wisk him away before they could undo his memories of the place–despite his tortured pleas to the contrary.

Mankind had reached out to the stars and discovered they were woefully behind technologically and intellectually. Mankind retreated and spend a million years improving his intellectual underpinnings.

There may be some bits about a sentient creation of man’s that possessed a perfect memory of the past. But that might be from another book. This being explained that the charred parabolic valley was not from fighting aliens, but from destroying the moon when it got too close.

Does anyone have any idea what book this was?

Sounds a bit like Arthur C. Clarke’s The City and the Stars, but some of the details aren’t quite the same.

So I’m going to take a stab and say that it’s Clarke’s Against the Fall of Night, a slightly earlier novel (and one which he rewrote into City). Unfortunately, I haven’t read Against, so I can’t be sure.

I’ve read both, and I can’t recall Against the Fall of Night being that different. Sure it wasn’t the same, but I don’t remember any duplicating machine. If that is it, do yourself a favor, and read The City and the Stars instead. It’s by far a better book.

They’re right – including that City is a vast improvement on Night.

G.B.H. Hornswoggler, That really sounds like it. I read some summaries on it and Alvin certainly is the protaganist. The title even sounds familiar.


As for the replicating machine. He and his robot entered a large utility area. The lights were very bright, as they were not for human eyes. The machine had instructions to “think clearly”, which he saw as an insult aimed at less mentally abled humans of past millenia. After the duplication he had to sign for it. The pen was in a clear substance that let him sign but not pull the pen out. The prior signature was somebody many, many thousands(millions?) of years ago, a famous person.

The robot floated around and had tentacle-like appendages. Alvin and the robot eventually hooked up with the robot’s space ship, which was resting in the sand outside Diaspar. The robot had a special area in the ship where it fit in like a hand in a glove. Having a duplicate proved very handy for some reason I can’t remember.

Thanks all!